def test_find_symbol_rate(self):
self.test_name = 'find_symbol_rate() test'
self.trial_count = 40
for i in xrange(self.trial_count):
self.update_progress(i+1)
freq = random.randrange(100, 10000)
# construct a list of edges with random spans
e = []
t = 0.0
for _ in xrange(200):
n = random.randrange(1, 5)
t += n / freq
e.append((t,1)) # we maintain state at constant 1 since find_symbol_rate() doesn't care
spectra = random.randrange(2, 5)
for s in xrange(spectra, 1, -1):
detected_rate = decode.find_symbol_rate(iter(e), spectra=s)
if detected_rate > 0:
break
# assertAlmostEqual() can't evaluate the closeness of two integers
# since it doesn't incorporate relative error
equal = tsup.relativelyEqual(detected_rate, freq, epsilon=0.01)
# print('sr', detected_rate, freq, equal)
if not equal:
print(' num spectra:', spectra)
print(e)
self.assertTrue(equal, msg='symbol rate mismatch {0} != {1}'.format(detected_rate, freq))
def __init__(self, channels, timescale=1.0e-12, date=None, comment=None):
'''
channels (sequence of VCDChannel)
A sequence of channel definitions
timescale (float or string)
Set the VCD timescale as a power of 10.
If a float, the value is used to establish the timescale.
If a string, it must match a channel name from channels. The symbol rate
of the named channel is determined and a raw timescale is derived from
1.0 / (4 * symbol rate). In both cases the raw value will be coerced to
a valid power of 10.
date (datetime or None)
An optional datetime for the VCD header. If absent the current time is used.
comment (string or None)
An optional comment to include in the header.
Raises ValueError if the timescale channel cannot be found or the symbol rate cannot
be determined.
'''
self._date = date
self.comment = comment
self.channels = channels
try:
ts = float(timescale)
except ValueError: # Assume it's a string
# Find channel name in channels
ts_data = None
for c in self.channels:
if c.name == timescale:
ts_data = c.states
break
if ts_data is not None:
sym_rate = decode.find_symbol_rate(iter(ts_data))
if sym_rate == 0:
raise ValueError('Unable to determine automatic timescale')
ts = 1.0 / (4 * sym_rate)
else:
raise ValueError('Channel not found: "{}"'.format(timescale))
self._timescale = coerce_timescale(ts)
def __init__(self, channels, timescale=1.0e-12, date=None, comment=None):
'''
channels (sequence of VCDChannel)
A sequence of channel definitions
timescale (float or string)
Set the VCD timescale as a power of 10.
If a float, the value is used to establish the timescale.
If a string, it must match a channel name from channels. The symbol rate
of the named channel is determined and a raw timescale is derived from
1.0 / (4 * symbol rate). In both cases the raw value will be coerced to
a valid power of 10.
date (datetime or None)
An optional datetime for the VCD header. If absent the current time is used.
comment (string or None)
An optional comment to include in the header.
Raises ValueError if the timescale channel cannot be found or the symbol rate cannot
be determined.
'''
self._date = date
self.comment = comment
self.channels = channels
try:
ts = float(timescale)
except ValueError: # Assume it's a string
# Find channel name in channels
ts_data = None
for c in self.channels:
if c.name == timescale:
ts_data = c.states
break
if ts_data is not None:
sym_rate = decode.find_symbol_rate(iter(ts_data))
if sym_rate == 0:
raise ValueError('Unable to determine automatic timescale')
ts = 1.0 / (4 * sym_rate)
else:
raise ValueError('Channel not found: "{}"'.format(timescale))
self._timescale = coerce_timescale(ts)
def test_find_symbol_rate(self):
self.test_name = 'find_symbol_rate() test'
self.trial_count = 40
for i in xrange(self.trial_count):
self.update_progress(i + 1)
freq = random.randrange(100, 10000)
# construct a list of edges with random spans
e = []
t = 0.0
for _ in xrange(200):
n = random.randrange(1, 5)
t += n / freq
e.append(
(t, 1)
) # we maintain state at constant 1 since find_symbol_rate() doesn't care
spectra = random.randrange(2, 5)
for s in xrange(spectra, 1, -1):
detected_rate = decode.find_symbol_rate(iter(e), spectra=s)
if detected_rate > 0:
break
# assertAlmostEqual() can't evaluate the closeness of two integers
# since it doesn't incorporate relative error
equal = tsup.relativelyEqual(detected_rate, freq, epsilon=0.01)
# print('sr', detected_rate, freq, equal)
if not equal:
print(' num spectra:', spectra)
print(e)
self.assertTrue(equal,
msg='symbol rate mismatch {0} != {1}'.format(
detected_rate, freq))
def ethernet_decode(rxtx,
tag_ethertypes=None,
logic_levels=None,
stream_type=stream.StreamType.Samples):
'''Decode an ethernet data stream
This is a generator function that can be used in a pipeline of waveform
procesing operations.
Sample streams are a sequence of SampleChunk Objects. Edge streams are a sequence
of 2-tuples of (time, int) pairs. The type of stream is identified by the stream_type
parameter. Sample streams will be analyzed to find edge transitions representing
0 and 1 logic states of the waveforms. With sample streams, an initial block of data
is consumed to determine the most likely logic levels in the signal.
rxtx (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream representing a differential ethernet signal.
tag_ethertypes (sequence of int or None)
The ethertypes to use for identifying 802.1Q tags. Default is 0x8100, 0x88a8, and 0x9100.
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the can parameter represents either Samples
or Edges
Yields a series of EthernetStreamFrame objects. Each frame contains subrecords marking the location
of sub-elements within the frame. CRC errors are recorded as an error status in their
respective subrecords.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
Raises StreamError if ethernet speed cannot be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
s_rxtx_it, logic_levels = decode.check_logic_levels(rxtx)
else:
s_rxtx_it = rxtx
hyst_thresholds = decode.gen_hyst_thresholds(logic_levels,
expand=3,
hysteresis=0.05)
rxtx_it = decode.find_multi_edges(s_rxtx_it, hyst_thresholds)
#print('## logic levels:', logic_levels, hyst_thresholds)
else: # The streams are already lists of edges
rxtx_it = rxtx
# Detect speed of ethernet
buf_edges = 150
min_edges = 100
# tee off an iterator to determine speed class
rxtx_it, speed_check_it = itertools.tee(rxtx_it)
# Remove Diff-0's #FIX: need to modify to work with 100Mb and 1Gb Enet
speed_check_it = (edge for edge in speed_check_it if edge[1] != 0)
symbol_rate_edges = itertools.islice(speed_check_it, buf_edges)
# We need to ensure that we can pull out enough edges from the iterator slice
# Just consume them all for a count
sre_list = list(symbol_rate_edges)
if len(sre_list) < min_edges:
raise stream.StreamError(
'Unable to determine Ethernet speed (not enough edge transitions)')
del speed_check_it
#print('## sym. rate edges len:', len(sre_list))
raw_symbol_rate = decode.find_symbol_rate(iter(sre_list), spectra=2)
#print('### raw sym rate:', raw_symbol_rate)
# For 10baseT (10MHz Manchester) the symbol rate will be 20MHz
# For 100BaseTX the symbol rate will be 31.25MHz?
if raw_symbol_rate < 25e6:
bit_period = 1.0 / 10.0e6
else:
raise stream.StreamError('Unsupported Ethernet speed: {}'.format(
eng_si(raw_symbol_rate, 'Hz')))
if stream_type == stream.StreamType.Samples:
# We needed the bus speed before we could properly strip just
# the anomalous SE0s
min_se0 = bit_period * 0.2
rxtx_it = decode.remove_transitional_states(rxtx_it, min_se0)
mstates = manchester_decode(rxtx_it, bit_period)
for r in _ethernet_generic_decode(mstates, tag_ethertypes=tag_ethertypes):
yield r
def ethernet_decode(rxtx, tag_ethertypes=None, logic_levels=None, stream_type=stream.StreamType.Samples):
'''Decode an ethernet data stream
This is a generator function that can be used in a pipeline of waveform
procesing operations.
Sample streams are a sequence of SampleChunk Objects. Edge streams are a sequence
of 2-tuples of (time, int) pairs. The type of stream is identified by the stream_type
parameter. Sample streams will be analyzed to find edge transitions representing
0 and 1 logic states of the waveforms. With sample streams, an initial block of data
is consumed to determine the most likely logic levels in the signal.
rxtx (iterable of SampleChunk objects or (float, int) pairs)
A sample stream or edge stream representing a differential ethernet signal.
tag_ethertypes (sequence of int or None)
The ethertypes to use for identifying 802.1Q tags. Default is 0x8100, 0x88a8, and 0x9100.
logic_levels ((float, float) or None)
Optional pair that indicates (low, high) logic levels of the sample
stream. When present, auto level detection is disabled. This has no effect on
edge streams.
stream_type (streaming.StreamType)
A StreamType value indicating that the can parameter represents either Samples
or Edges
Yields a series of EthernetStreamFrame objects. Each frame contains subrecords marking the location
of sub-elements within the frame. CRC errors are recorded as an error status in their
respective subrecords.
Raises AutoLevelError if stream_type = Samples and the logic levels cannot
be determined.
Raises StreamError if ethernet speed cannot be determined.
'''
if stream_type == stream.StreamType.Samples:
if logic_levels is None:
s_rxtx_it, logic_levels = decode.check_logic_levels(rxtx)
else:
s_rxtx_it = rxtx
hyst_thresholds = decode.gen_hyst_thresholds(logic_levels, expand=3, hysteresis=0.05)
rxtx_it = decode.find_multi_edges(s_rxtx_it, hyst_thresholds)
#print('## logic levels:', logic_levels, hyst_thresholds)
else: # The streams are already lists of edges
rxtx_it = rxtx
# Detect speed of ethernet
buf_edges = 150
min_edges = 100
# tee off an iterator to determine speed class
rxtx_it, speed_check_it = itertools.tee(rxtx_it)
# Remove Diff-0's #FIX: need to modify to work with 100Mb and 1Gb Enet
speed_check_it = (edge for edge in speed_check_it if edge[1] != 0)
symbol_rate_edges = itertools.islice(speed_check_it, buf_edges)
# We need to ensure that we can pull out enough edges from the iterator slice
# Just consume them all for a count
sre_list = list(symbol_rate_edges)
if len(sre_list) < min_edges:
raise stream.StreamError('Unable to determine Ethernet speed (not enough edge transitions)')
del speed_check_it
#print('## sym. rate edges len:', len(sre_list))
raw_symbol_rate = decode.find_symbol_rate(iter(sre_list), spectra=2)
#print('### raw sym rate:', raw_symbol_rate)
# For 10baseT (10MHz Manchester) the symbol rate will be 20MHz
# For 100BaseTX the symbol rate will be 31.25MHz?
if raw_symbol_rate < 25e6:
bit_period = 1.0 / 10.0e6
else:
raise stream.StreamError('Unsupported Ethernet speed: {}'.format(eng_si(raw_symbol_rate, 'Hz')))
if stream_type == stream.StreamType.Samples:
# We needed the bus speed before we could properly strip just
# the anomalous SE0s
min_se0 = bit_period * 0.2
rxtx_it = decode.remove_transitional_states(rxtx_it, min_se0)
mstates = manchester_decode(rxtx_it, bit_period)
for r in _ethernet_generic_decode(mstates, tag_ethertypes=tag_ethertypes):
yield r
